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Dengue Fever

Group presentation on

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Introducing Us

Alvi Ehsan

Maimuna Mahmud

Taslima Khanam Lima

Gaulib Haidar

Sudipto Bala(L)

Sunzida Haque

151-2614-630

151-0609-630

132-0225-020

151-0898-630

151-0885-630

151-2131-030

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Contents

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Dengue

-What it is and how it occurs

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Dengue

Dengue fever known as break-bone fever is a mosquito-borne tropical disease caused by the dengue virus. However Symptoms of dengue fever include fever, headache, muscle & joint pains, and a characteristic skin rash that is similar to measles.

In a small proportion of cases the disease develops into the life-threatening dengue hemorrhagic fever, resulting in bleeding, low levels of blood platelets and blood plasma leakage.

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Dengue

Dengue is not transmitted directly from person-to-person. Dengue is transmitted by several species of mosquito.

As there is no commercially available vaccine, prevention is sought by reducing the habitat and the number of mosquitoes and limiting exposure to bites.

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History & origin

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Transmission

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Signs and symptoms

Many people, especially children and teens, may experience NO signs or symptoms during a mild case of dengue fever. When symptoms do occur, they usually begin four to 10 days after one is bitten by an infected mosquito.

Signs and symptoms of dengue fever most commonly include:

Fever, as high as 106 F (41 C˚) Headaches

Muscle, bone and joint pain

Pain behind eyes

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Signs and symptoms

One may also experience:

Widespread rash

Nausea and vomiting

Rarely, minor bleeding from gums or nose

Red spots or patches on the skin

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Signs and symptoms

One may also experience:

o Widespread rasho Nausea and vomitingo Rarely, minor bleeding from gums or noseo Red spots or patches on the skin

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Signs and symptoms

Most people recover within a week or so. In some cases, symptoms worsen and can become life-threatening. Blood vessels often become damaged

and leaky. And the number of clot forming cells (platelets) in one’s bloodstream drops. This can cause:

Bleeding from nose and mouth

Severe abdominal pain

Persistent vomiting

Bleeding under the skin, which may look like bruising

Problems with lungs, liver and heart

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Signs and symptoms

Typically, people infected with dengue virus are asymptomatic (80%) or only have mild symptoms such as an uncomplicated fever, others have more severe illness (5%), and in a small proportion it is life-threatening.

The incubation period (time between exposure and onset of symptoms) ranges from 3 to 14 days, but most often it is 4 to 7 days.

Children often experience symptoms similar to those of the common cold and gastroenteritis (vomiting and diarrhea) and have a greater risk of severe complications, though initial symptoms are generally mild but include high fever.

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Signs and symptoms – clinical phase of infection

The course of infection is divided into three phases

Febrile Critical Recovery

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Signs and symptoms – clinical phase of infection

The course of infection is divided into three phases

Febrile Critical Recovery

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Signs and symptoms – Febrile phase

High fever, potentially over 40°C (104°F) associated with generalized pain and a headache; this usually lasts 2 to 7 days. The fever usually is breaking and then returning for one or two days.

Nausea and vomiting.

Measles-like rash, flushed skin may occur anytime from the first day of symptoms to the first week. A rash described as "islands of white in a sea of red" has also been described.

Some petechiae (small red spots that do not disappear when the skin is pressed, which are caused by broken capillaries) can appear.

Some mild bleeding from the mucous membranes of the mouth and nose may occur.

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Signs and symptoms – Critical phase

In some people, the disease proceeds to a critical phase as fever resolves. The symptoms of this phase are:

Leakage of plasma from the blood vessels typically lasting one to two days.

Decreased blood supply to vital organs.

Organ dysfunction and severe bleeding may occur, typically from the gastrointestinal tract.

Shock or dengue shock syndrome and hemorrhage (dengue hemorrhagic fever) may occur (less than 5% of all cases of dengue).

Those who have previously been infected with other serotypes of dengue virus ("secondary infection") are at an increased risk. This critical phase, while rare, occurs relatively more commonly in children and young adults.

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Signs and symptoms – Recovery phase

Recovery occurs next, with:

Resorption of the leaked fluid into the bloodstream, usually lasting two to three days.

The improvement is often striking, and can be accompanied with severe itching and a slow heart rate.

Another rash may, which is followed by peeling of the skin.

A fluid overload state may occur.

If it affects the brain, it may cause a reduced level of consciousness or seizures.

A feeling of fatigue may last for weeks in adults.

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Associated problems

Dengue can occasionally affect several other body systems, either in isolation or along with the classic dengue symptoms. A decreased level of consciousness occurs in 0.5–6% of severe cases, which is attributable either to inflammation of the brain by the virus or indirectly as a result of impairment of vital organs, for example, the liver.

Other neurological disorders have been reported in the context of dengue, such as transverse myelitis and Guillain-Barré syndrome.

Infection of the heart and acute liver failure are among the rarer complications.

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Prevention

There are no approved vaccines for the dengue virus. Prevention thus depends on control of and protection from the bites of the mosquito that transmits it. The World Health Organization recommends an Integrated “Vector Control program” consisting of five elements:

1. Advocacy, social mobilization and legislation to ensure that public health bodies and communities are strengthened

2. Collaboration between the health and other sectors (public and private)

3. An integrated approach to disease control to maximize use of resources

4. Evidence-based decision making to ensure any intervention is targeted appropriately

5. Capacity-building to ensure an adequate response to the local situation

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Control

The primary method of controlling Aedes aegypti is by eliminating its habitats. This is done by:

1. Adding insecticides or biological control agents to affected area.

2. Generalized spraying with organophosphate or pyrethroid insecticides

3. Reducing open collections of water through environmental modification

Some other methods of controlling dengue are: Prevent mosquito bites by wearing clothing that fully covers the skin

Using mosquito netting while resting

Applying insect repellent (DEET being the most effective).

DEET, is a slightly yellow oil. It is the most common active ingredient in insect repellents. It is intended to be applied to the skin or to clothing, and provides protection against mosquitos, ticks, fleas, chiggers, leeches, and many other biting insects.

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Treatment

There is no specific medicine to treat dengue infection. If one thinks one may have dengue fever, one should:

Use pain relievers with acetaminophen

Avoid medicines with aspirin, which could worsen bleeding.

Rest

Drink plenty of fluids

Must see a doctor.

If one starts to feel worse in the first 24 hours after fever goes down, one must get to a hospital immediately to be checked for complications.

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Treatment

More severe variations of dengue fever (hemorrhagic and shock syndrome) usually require additional supportive treatments. These patients often require hospitalization with the following medical services:

IV hydration

Blood transfusions

Platelet transfusions

Blood pressure support

Other intensive-care measures

Consultation with infectious-disease and critical-care specialists is often advised to optimize patient care.

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Treatment - Self-Care at Home

Home care for dengue fever is simply supportive care.

Good oral hydration, pain control with Tylenol (or other non-NSAIDs) is usually adequate treatment for most people.

However, there is no role for home care in patients with dengue hemorrhagic fever or for dengue shock syndrome; depending on the patient's condition, many clinicians consider these conditions to be medical emergencies.

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Dengue throughout the globe

o Dengue is common inMore than 110 countries:

1. Malaysia2. Bangladesh3. India4. Pakistan5. Brazil6. USA

o It infects 50 to 528 million people worldwide a year, leading to half a million hospitalizations, and approximately 25,000 deaths.

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Dengue throughout the globe– Southeast Asia

For the decade of the 2000s, countries of Southeast Asia were estimated to have about 3 million infections and 6,000 deaths annually.

Malaysia Thailand Burma Cambodia East Timor Indonesia Laos

Brunei Philippines Singapore Vietnam

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Dengue throughout the globe

Worldwide dengue distribution, 2006.

Red: Epidemic dengue Blue: Aedes aegypti

o The geographical distribution is around the equator. Of the 2.5 billion people living in areas where it is common, 70% are from Asia and the Pacific.

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Dengue throughout the globe – Africa

34 African countries have reported dengue including: Egypt

South Africa

Aedes aegypti mosquitoes are present in at least 9 African countries including: Niger

Chad

Data are not available for 5 African countries: Western Sahara

Morocco

Algeria

Tunisia

Libya

Dark Red = Countries in which dengue has been reportedLight Red = Countries in which dengue has not been reported but where Aedes aegypti mosquitoes are presentWhite = Countries for which data are not available

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Dengue throughout the globe

Dengue fever, which was once confined to Southeast Asia, has now spread to: Southern China

Countries in the Pacific Ocean

America, and

Possess a threat to Europe.

Rates of dengue increased 30 fold between 1960 and 2010. This increase is believed to be due to a combination of: Urbanization

Population growth

Increased international travel, and

Global warming.

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Why is dengue alarming?

Country Number of Cases Deaths

Brazil 56,882 39

Paraguay 27,000 31

Thailand 52,008 50

Philippines 18,885 115

Country Number of Cases Deaths

Brazil 205,000 78

Paraguay 70,000 35

Thailand  150,000 50

Philippines 42,500 200

Data of 2011 Data of 2013

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Research and development

Research efforts to prevent and treat dengue include:

1. Vector control

2. Vaccine development, and

3. Antiviral drugs

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Research and development – Vector control

A number of novel methods have been used to reduce mosquito numbers with some success including the placement of the guppy (millionfish or rainbow fish) or copepods in standing water to eat the mosquito larvae.

Attempts are ongoing to infect the mosquito population with bacteria of the Wolbachia genus, which makes the mosquitoes partially resistant to dengue virus.

There are also trials with genetically modified male A. aegypti that after release into the wild mate with females, and render their offspring unable to fly.

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Research and development – Vaccine development

There are ongoing programs working on a dengue vaccine to cover all four serotypes. Now that there is a fifth serotype this will need to be factored in.

As of 2012, a number of vaccines were undergoing testing. The most developed is based on a weakened combination of the yellow fever virus and each of the four dengue serotypes.

Two studies of a vaccine found it was 60% effective and prevented more than 80 to 90% of severe cases. It is hoped that the first products will be commercially available by 2015.

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Research and development –Antiviral Drugs

Apart from attempts to control the spread of the Aedes mosquito and work to develop a vaccine against dengue, there are ongoing efforts to develop antiviral drugs that would be used to treat attacks of dengue fever and prevent severe complications.